Contributors

Tuesday, August 13, 2013

The lecture (see link) details some research conducted by Professor Bruce Hollis on the supplementation of vitamin D during pregnancy and breastfeeding. There was a lot of controversy surrounding the data from this study, due to many perpetuating myths surrounding vitamin D supplementation and the misguided fears of over-supplementation.

Professor Bruce Hollis provides a very strong argument, based on the findings of this research, that giving 4000 IU a day to pregnant women and 6400 IU a day to breastfeeding women is not only safe but also necessary in avoiding deficiencies in both the mother and infant.

He explores the evolution of humans in order to explain why our vitamin D requirements are as high as they are in modern societies and how effected these levels are by lack of sun exposure, ethnicity and geographical location due to the variation of sunlight and intensity. He also argues that it is not possible to receive adequate amounts of vitamin D from diet alone, such as from fatty fish such as salmon, tuna and herring, milk with added vitamin D or the small amounts found in eggs and meats.

This study was motivated by the mounding evidence that vitamin D deficiency during pregnancy is a serious public health issue, affecting both the mother and foetus. Therefore, the importance of establishing the vitamin D requirements of the pregnant women is vital in preventing vitamin D deficiency. Yet regardless of this, the Institute of Medicine sets the recommended daily intake (RDA) at 600 IU per day.

This research study aims to evaluate the safety and effectiveness of high doses of vitamin D supplementation during pregnancy and breastfeeding in order to achieve vitamin D sufficiency. The study design was a randomized control, double-blind placebo study involving 516 patients of African American, Hispanic and Caucasian descent. It provided either 2000 IU or 4000 IU of vitamin D per day to pregnant mothers. Levels were then measured by the mean circulating 25 (OH) D (nmol/L).

There were no adverse effects found in this study, even though there have been medical claims that high doses of vitamin D will do damage to the foetus. The results of the data also indicate that if the “pool starts off empty”, meaning the mother had low vitamin D levels to begin with, small doses (i.e. 400 IU per day) do nothing to alter overall levels. However, supplementation of 2000 IU and 4000 IU daily resulted in a substantial rise in overall blood levels.

The need to supplement with such high levels of vitamin D can be explained in other ways, aside from our lack of daily exposure to the sun. Vitamin D has a short half-life of one day, a scientific term used to explain the time required for a quantity to fall to half of its value as measured at the beginning of the time period. This means that if vitamin D is not consistently being repleted each day, where is our vitamin D?

This study concluded that pregnant women need 40 ng/ml (100 nmol/l) to optimise the production of the active form of vitamin D. Levels lower than this were also found to compromise the absorption of calcium in the gut. It also plays a significant roll in immunity during pregnancy, including the altered immune response that adapts to the growth of the foetus by avoiding the auto-rejection of the presence of new tissue. It has also been shown to turn on the innate immune system, the first line of defence that enables us to fight infection.

The second aspect of this study was to determine the sufficient requirements for vitamin D supplementation in breastfeeding mothers to avoid deficient breast milk. It found that maternal supplementation of 400 IU per day and infant supplementation of 300 IU per day lead to significantly deficient vitamin D levels in breast milk.

Similar studies have been done involving the supplementation of 2000 IU per day to breastfeeding mothers and their breast milk was still found to contain insufficient levels of vitamin D.

It determined that supplementing 6400 IU of vitamin D per day by the mother was required to pass on adequate levels to her child. Such high doses are required by the mother as the parent compound gets transferred into the milk, meaning the infant receives higher doses of vitamin D in breast milk than if the infant were being directly supplemented. This is why supplementing a breastfeeding mother with adequate doses of vitamin D is so important both for her and for her child.

Ensure to consult with your doctor or healthcare professional before taking any supplements.

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